Combustion control



y 1931- R. P. BROWN 1,816,311

COMBUSTION CONTROL Original Filed Jan. 27, 1926 2 Sheets-Shout 1 INVENTOR APamouaafihfleouav Mk/WM ATTORNEY July 28, 1931. R. P. BROWN 1,816,311

COMBUSTION CONTROL Original Filed Jan. 27, 1926 2 Sheets-Sheet 2 INVENTOR I ATTOR'NEY l afented July 28, 1931 ;UNYIBATED STATES PATENT OFFICE m n 2. snow, or PHILADELPHIA, r nsunnm; ASSIGNOR. 'ro r1111 nnown ms'rnunmrm comrAnY, or PHILADELPHIA, PENNSYLVANIA, a coaroaarron or PENNSYLVANIA COMBUSTION CONTROL ori in l application filed January 27, .1926, Serial m. 84,077. Divided and this application filed October a, 1920. Serial No. 140,539.

Thejgeneral object-of my present invention is to provide an improved method and means for automatically 1e ulating the combustion in the combustion c amber of a furnace in such manner as to maintain good thermal efliciency while at the same time avoiding localfloverheating of portions of the combustion chamber of the apparatus heated. A more specific object of my invention is to provide improved means for automatically regulating the supply of fuel to a lurality of burners separately supplying eat .to different portions of the combustion chamber. To this end, I provide mechanism including means separately-responsive to the 7 temperature in the combustionchamber at 7 points adjacent the respective burners for so regulatingthe supplyof fuel to the different burners as to eliminate or minimize differences in temperature between the portions of the combustion chamber heated by the different burners. The mechanism just referred toin some cases may advantageously be associated with, or include means whereby the general combustion chamber temperature is varied in accordance with the demand or need for heat, and in conjunction therewith, other thermostatic means automatically responsive to variations in temperature of the fluid being heated, when it is desirable or necessary that the .fluid be maintained at a constanttemperature.

While the present invention in its broader aspects is adapted for use in furnaces of very difierent types employed for various purposes, the invention is of especialutility in controlling combustion conditions 1n tube 011 heaters or stills for heating petroleum oils portant to avoid local overheating o to a refiningtemperature. the operation of an oil heater, or still, it Is especiall 1many portions of the ,oil containing tubes, because of the injury to the tubes and to the value of the products of the refining operation rep, sulting from. such local overheating.

-' The variousfeatures of novelty;v which characterize my. invention 1 are pomtd, out

ever, its advantages and specific objects attalned with its use, reference should be had to the accompanying drawings and descript1ve matter in which I have described and lllust'rated prefered embodiments of my invention.

Ofthe drawings:

Fig. 1 is a diagrammatic representation of an oil refining tube still provided with one form of control provisions;

Fig. 2 is a view taken similarly to Fig. 1 lllu'strating a second form of control provisions; and

Fig. 3 is a view taken similarly to Fig. 1 illustrating a third form of control prov1s1ons.

In Fig. 1 I have diagrammatically illustrated an embodiment of the present invention including a tube oil heater or a tube still A of conventional type. As shown, the heater A comprises a furnace combustion chamber A beneath a bank of horizontal tubes B which are swept by the heating gases passing from the combustion chamber A to the furnace stack outlet A. The tubes B are connected at their ends so that the oil passes successively through tubes B at successively lower levels from an upper oil inlet to a lower oil outlet. The oil to be refined is su ggalied to the heater oilinlet by a fuel pump driven by a motor C shown as a steam motor at a speed depending on the adj ustment of a regulating valve C in the steam supply line to the motor. The heater A is heated by the combustion/effuel separately supplied to different portions of theco'mhustion chamber A by suitably spaced apart burners. As shown, there ,are two su'ch burn valves D and d. p I

g In the particular control system-shown 1n Fig. 1, the valve C is adjusted to increase and decrease the ,rate at which oil is passed I :"abetter understanding of the invention, howwithfparticularity in the claims annexed to? and,forminga'part of'this specification; For-through the tubes B- by the pump 0 as the temperature to which the 011 is heated in passing through the tubes falls below or rises plassin'gthrough the tubes B. The controller isthusj made responsive to the still oil exit temperature by means of a thermo-couple F like the voltmeter e of Fig. 3, having its terin erted in a thermometer well B in the path of o'ilflowat'or adjacent the still outlet. The terminals of the thermo-couple F are connected by conductors 8 and 9 to correspond ing terminals of the pyrometer controller Ea As shown, one terminal of the motor G is connected by a conductor 3 to the conductor. 1 forming one side of an electric current sup- 2 ply or power circuit. The controller E operates in response to the potential developed by the thermo-couple F to connect one terminal 6 of the motor G to the conductor 2 of the power circuit through a conductor 4 and thereby cause the motor G to rotate in a direction to throttle the flow through the valve C when the temperature to which the thermo-couple F is subjected falls below the redetermined oil temperature desired. (Jonversely, when the temperature to which the thermo-couple 1* is subjected exceeds said predetermined oil temperature the pyrometer controller E connects a second terminal 5 of the motor G to the conductor 4 and thereby to the supply conductor 2 whereupon the motor G rotates in the direction to 0 en or increase the flow through the valve H The pyrometer controller E may be ofany usual or suitable form of instrument-for the purpose. In general it includes a voltmeter minals connected by the thermo-couple F, and includes a switch mechanism controlled by the voltmeter pointer and serving to connect the motor terminal 6 to the conductor 4 when the oil temperature is below the predetermined value and to connect the motor terminal 5 to the conductor 4 when the oil temperature" is above the predetermined value. The switchmechanism in an instrument of this type is ordinarily actuated by a motor or other relay which may be energized from the suppl conductors 1 and- 2 through the conductors and 7 I have not thought it necessary to illustrate and describe in detail the construction of the pyrometer con- -troller E for the reason that the present invention does not depend on the specific form of the controller and various forms of control instruments suitable for the purpose are known. For example, the controller E may be of the type disclosed in the patent to valves D and d as required to maintain an approximately constant temperature in the portion .of the combustion chamber A into c thermo-couples FD and fd controls the corresponding burner may be identical with those prev1ously described through which the thermo-co'uple F controls the motor G. In

' practice, however, -I prefer to employ in lieu of a separate pyrometer controlled in conjunction with each of the thermo-couples FD and fd, a multiple'controller EA to which each of the thermo-couples FD and fd may be connected as the thermo-couple F is connected to the controller E, and to which each of the motors GD and gel may be connected as the motor G is connected to the controller E. The controller EA may be of well known type, and need not difier from the controller E except that it includes a switch mechanism i for connecting the controller voltmeter to the thermo-couple FD and to the thermoof a minute or so. At the same time at which the. thermo-couple FD is connected to the controller EA, the control provisions of the controller EA are connected to the conductors '50 'and pertaining to the motor GD, and

the control provisions of the controller EA are connected to the corresponding conductors pertaining to the motor yd when the thermo-couple id is operatively connected to the controller. a With the apparatus shown in Fig. 1, fuel is supplied to the burners D and d as required to maintain the temperature in these portions of the combustion chamber approximately constant and insures, of course, an approximately constant general combustion chamber temperature. In consequence, fuel is sup,-

plied to the burners D and d as required to which the corresponding burner opens. To

"couple id in regular alternation at intervals a to a'desirable uniformity in the temperature gfr different portions of the combustion cham- When as is usually the case, an oil still furname is provided with more than two. burners, the distribution of the fuel burned by the different burners may be effected by control provisions analogous to those shown in Fig. 1 including a theremo-couple for measuring the combustion chamber temperature adjacent each of the different burners and a multiple controller operatively related with each such thermo-couple and with the corresponding fuel valve relay motor in the same manner as the two thermo-couples FD and fd, and the two motors GD and gd are associated with the controller EA of Fig. 1. In some cases it may be desirable to provide a signal device to light a lamp or ring a bell when as because of some abnormal condition the control provisions fail to prevent the oil exit temperature from becoming unduly high. In Fig. 1 Ihave illustrated a signal device for this purpose comprising a voltmeter H connected in parallel with the controller E and arranged to haveits pointer H close a signal circuit on a predetermined increase in the exit tem erature above that normally maintained. s shown in Fig. 1, the signal circuit includes a hell I, a source of current I, and a contact H engaged by the pointer H on a predetermined rise in temperature. I

The advantages of regulating the distribution of fuel to the different burners of a tube still bythermally responsive means responsive to combustion chamber temperatures at oints adjacent the diflerent burners may e obtained with other means than those shown in Fig. 1, and of course in furnaces not having the control provisions shown in Fig. 1 for maintaining a definite relation between the oil exit and combustion chamber temperature.

For example, as shown in Fig. 2, I may employ a form of oil heater control provisions differing from those hereinbefore described'in that the rate of oil flow through the still tubes is maintained constant by employing a constant speed motor CA to drive the feed pump C. In this form of invention the desired constant exit oil temperature is obtained by adjusting the fuel supply to one or more of the burners in response to changes in the oil exit temperature while employing other provisions to control the distribution of fuel to the burner or burners first described and to the remaining burner or burners. In Fi 2 the motor 901 regulating the supply of uel to-the burned d is controlled through a controller E by the exit oil temperature thermo-couple F just as the thermocouple F and the controller E control the motor G in Fig. 1. The supply of fuel to the burner D is regulated by a motor GD poses the other.

controlled through a controller EC, by thermo-couples FD and fd responsive tothe combustion chamber temperatures atpoints adjacent burners D and d. The thermocouples FD and fd-are connected in series with one another and with the voltmeter of the control instrument EC in such fashion that the voltage of each thermo-couple o In consequence when t e temperature of the thermo-couple d rises above that of the thermo-co'uple D, ,the controller EC is operated to start the motor GDinto rotation in the direction toincrease the supply of fuel to the burner D. Conversely, when the temperature to which the thermo-couple FD is subjected exceeds that to which the thermo-couple fd is subjected, the controller EC sets themotor GD intO. operation in the direction to decrease the supply of fuel to the burner D. The controller EC may be exactly like the controller E but will ordinarily be adjusted so that the neutral control position of the voltmeter will correspond to the natural zero positiontemperature with a constant rate of oil flow through the still tubes, and in which the distribution of fuel to the different burners is regulated to minimize differences in combustion chamber temperatures adjacent the different members. The apparatus shown in Fig. 3 for securing the operative results just referred to are different, however, from those shown in Fig. 2. In Fig. 3 the distribution of fuel to the different burners D and d is regulated and controlled by motors GD and gal, and thermo-couples FD and id, like the correspondingly designated motors and thermo-couples of Fig. 1, and operatively related for this purpose with a controller ED. The latter may be identical-with the controller EA except that the controller ED includes provisions not employed in the controllerEA, for varying the constant, so to speak, of the controller voltmeter so that the controller. tends to maintain different combustion chamber temperatures as required to obtain the desired approximately constant exit oil temperature.

In Fig. 3, 6 represents the voltmeter element of the controller ED, and e and 6 represent control contacts closed by the deflection of the voltmeter pointer e in one direction or the other. When the engages the contacts 6 the motor D or the motor gd is set into operation in one direction depending on the then adjustment of ointer e' switch 6*. Conversely when the pointer e engages the contacts e the motor GD or gel is set into rotation in the opposite direction according to the position of the switch 6.

- The controller ED includes a, switch 6 which is operated in' synchronism with the switch meter 6, and the control contacts 6 and e are operatively connected to the terminals of the motor gcZ. Insofar as above described the control instrument ED may be identical with the control instrument EA of Fig. 1.

The provisions for varying the constant of the voltmeter 0, shown in Fig. 2, comprise a voltmeter EE' having its terminals connected to the terminals 8 and 9 of the thermo-couple F and having its movable pointer 6 adapted to engage a contact 6 on a predetermined increase in the exit oil temperature above the predetermined desired temperature, and adapted to engage a contact a when the exit temperature falls below the predetermined value. A resistance R is normally connected in series with the voltmeter 6. This resistance is short circuited by a low resistance shunt including the pointer e of the voltmeter EE and the contact 6 when the rise above normal of the exit oil temperature swings the pointer 6 into engagement with the contact 6 The change in the constant of the voltmeter e produced when the resistance R is thus short-circuited, causes its pointer e to engage the control contacts 6 when the temperatures to which the thermocouples FD and fd are subjected are lower than would be required to bring the pointer 6 into engagement with the contacts 6 when the resistance R is in circuit. When the resistance R is short circuited, the controller ED operates to maintain a lower combustion chamber temperature than is maintalned when the resistance R is in circuit, as should be the case, since the resistance R is short circuited as a result of a rise in the exit oil temperature above the normal value. When the exit oil temperature decreases below the normal value far enough to cause the pointer e of the voltmeter EE to engage the contact 0 some of the current generated by the thermo-couple voltage is diverted away from the voltmeter e by the shunt circuit across the terminals of the voltmeter e which includes the pointer e of the voltmeter EE, the contact 0 and the variable resistance R The effect of thus diverting the current away from the voltmeter e is to increase the combustion chamber temperature which the controller ED tends to maintain and thereby increase the exit oil temperature to its normal value.

Any of the forms of automatic controllers E, EA, etc. illustrated herein may have pro.- visions such, for example, as those illustrated in the Patent No. 1,715,895, issued June 4, 1929, to Frederick WV. Side and myself, for making the extent of movement imparted to the controller motor on each actuation of the controller greater when the deflection of the controller voltmeter from its neutral control position is relatively large, than when said deflection is relatively small. 1

Where the type of oil burners employed and the conditions regulating the supply of combustion air to the combustion chamber are not adapted to make the supply of combustion supporting air vary as required to maintain a sufliciently uniform fuel and air ratlo, provisions may be made for adjusting air supply regulating dampers or valves as and when the burner regulating valve D and d are adjusted. I have not thought it necessary to illustrate such provisions as they will not be required in many cases, and moreover those provisions may be duplicates of those employed to control the valves D and 0i. v

Certain novel methods and features of construction and arrangement disclosed but not claimed herein are claimed 'in my prior appllcation, Serial No. 84,07 7 nled January 27, 1926, of which this application is a division. The automatic adjustment of the furnace temperature maintained, in response to variatlons in oil temperature provided for in the arrangement illustrated in Fig. 3 hereof, but not claimed herein, is claimed in my copendmg application, Serial No. 198,298, filed June 11, 1927.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of my invention as set forth in the appended claims and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

Having now described my invention, What I claim as new and desire to secure by Letters Patent, is

1. The method of regulating combustion in a combustion chamber having a plurality of burners which consists in regulating the distribution of fuel among the diflerent burners in automatic response to the temperatures of the combustion chamber portions adjacent the different burners as required to maintain a predetermined relation between said temperatures.

2. In supplying heat to a combustion chamber by means of a plurality vof burners, the method of equalizing the combustion chamber temperatures which consists in increasing or decreasing the supply of fuel to one of said burners in automatic response to relative variations in the temperatures of. portions of said chamber adjacent the different burners.

I 3. In heating oil to a refining temperature in a heater comprising a combustion chamber and a plurality of fuel burners opening to said chamber, the improvement which consists in automatically re lating the distribution of fuel to the different burners in and a controller connected to response to the temperatures of portions of the combustion chamber adjacent the different burners so as to thereby gequalize said temperatures. 1

4. In a combustion chamber the combination with a plurality of burners separately supplying heat to dlfierent portions of said chamber, of control mechanism including elements respectively associated with, and responsive to the temperatures adjacent the different burners for regulating the relative operation of thedifierent burners.

5. In a combustion chamber, the combination with a plurality of burners opening to said chamber at different oints, of a temperature responsive device a j said temperature responsive devices and regulating the relative supply of fuel to the different burners.

6. In an oil heater comprising a combustion chamber and a pluralit of fluid fuel burners opening to said cham er at different points, the combination therewith of devices responsive to the temperature in the combustion chamber at points adjacent the different burners for regulating the distribution of fuel to the different burners.

Signed at Philadelphia, in the county of Philadelphia and State of Pennsylvania, this 7th day of October, A. D. 1926.

' RICHARD P. BROWN.

acent each burner, 

